Melanin exists widely in the world of animals and plants. It is known that it protects eyes and skin from harmful ultraviolet rays through absorbing them. Conventionally, it is known that a synthetic melanin (other than the melanin which exists in the world of animals and plants) is obtained by oxidizing a melanin precursor, such as a catechol, etc., in an aqueous solution. So, it has been expected that a melanin-containing laminated body for optical purposes which can protect eyes from ultraviolet rays by using these characteristics of melanin would be developed.
Conventionally, methods for producing a water-soluble melanin that is obtained by oxidizing a melanin precursor, such as a catechol, etc., in an aqueous solution, have been disclosed. (See References 1 and 2 below.)
A use as a functional film has been proposed by extracting the melanin, obtained as above, in the presence of salts with an organic solvent. (See Reference 1 below.)
Reference 1: Official Gazette of Japanese Patent Early-publication (Kokai No. Hei.
Reference 2: Official Gazette of Japanese Patent Early-publication (Kokai No.